Mounting of the camshaft in an overhead camshaft engine



June 1968 6. DE COYE DE CASTELET 3,388,614

MOUNTING OF THE CAD/[SHAFT IN AN OVERHEAD CAMSHAFT ENGINE Filed Oct. 7, 1965 2 Sheets-Sheet 1 177M? for Ga'idn De Zoye De Cade/e June 3, 1968 (3. DE COYE DE CASTELET 3,338,614

MOUNTING OF THE CAMSHAFT IN AN OVERHEAD CAMSHAFT ENGINE Filed Oct. 7, 1965 2 Sheets-Sheet 2 FIG.4

United States Patent 3,388,614 MOUNTING OF THE CAMSHAFT IN AN OVERHEAD CAMSHAFT ENGINE Gaetan de Coye de Castelet, Billancourt, France, assignor to Regie Nationale des Usines Renault, Billancourt,

Seine, France Filed Get. 7, 1965, Ser. No. 493,671 Claims priority, application France, Jan. 4, 1965, 710, Patent 1,428,547 3 Claims. (Cl. 74-567) ABSTRACT OF THE DISCLOSURE A camshaft for an internal combustion engine having an overhead mounted camshaft. The camshaft permits valve clearance regulation without adjustment of either the camshaft drive means or the setting of the timing gear. The camshaft is formed in two interlocking portions, one portion of which bears the cams and the other portion of Which is the drive. The drive portion is rotatably secured in the engine and the cam portion is detachable from the drive portion to make the necessary adjustments.

The invention relates to the mounting of the camshaft in an overhead camshaft engine.

In engines of this type, whose camshaft is driven by chain, serrated belt or any other means, it is necessary to remove this drive before dismounting the shaft.

As a result, each time the shaft is dismounted it is necessary to re-set the timing-gear, an operation which takes up a certain amount of time and which may or may not be properly carried out. Now, it is necessary to dismount the camshaft whenever it is desired to re-set the valve clearance, such re-setting being obtained in engines where the camshaft acts directly on the valves by means of intermediate elements interposed between the tappets and the ends of the valve stems, and these intermediate elements can be removed and replaced only if the shaft is dismounted.

The present invention concerns an improvement in the mounting of the camshaft with the object of avoiding having to re-set the timing-gear each time that the said shaft has to be dismounted. This improvement consists essentially in making the camshaft in two parts, one carrying the cams and the other the driving device, these two parts being assembled in such a manner that the part comprising the cams can be dismounted whilst the second part remains in position which, of course, means that the setting of the timing-gear is no longer aifected when the part comprising the cams is dismounted to adjust the valve clearance.

The invention will now be described in detail with reference to the accompanying drawings which show by way of non-limitative example:

FIGURE 1 a camshaft made in two parts according to the invention, these two parts being shown separate;

FIGURE 2 the same parts engaged in one another;

FIGURE 3 the same parts shown in the assembled state; and

FIGURE 4 shows the assembled parts mounted in an engine.

Referring now to FIGURE 1, it will be seen that the camshaft is made in two parts, a part 1 which comprises the cams and another part 2 which comprises the driving Patented June 18, 1968 device which is shown here by way of example as being constituted by a toothed Wheel 3 driven by a chain 4.

The toothed wheel 3 is fast with a shaft 5 which is journalled with clearance in a bearing, see FIG. 4, so that the part 2 can remain in position when the part 1 is dismounted.

In order to permit this dismounting the connection between the parts 1 and 2 is arranged, in a manner known per se, in the following way: the part 1 comprises at its end a circular plate 6 the diameter of which corresponds to that of the housing 7 formed in the plate carried by or formed on the toothed wheel 3.

In order to permit disengaging the part 1 from the part 2 in a diametral plane, which is necessary in view of the fact that the part 1 cannot be displaced longitudinally since it is retained in its thrust bearings such as 8, the circular plate 6 comprises cut-away edges 9 and the housing 7 of the plate of the toothed wheel 3 comprises corresponding recesses 10.

Therefore, the part 1 can be withdrawn from or introduced into the part 2 by displacing it in the direction of the arrow as FIGURE 1 shows, the part 1 being situated in such a manner that the cut-away edges of the plate 6 and the recesses 10 are directed in the sense of this arrow. When the part 1 has been engaged in the part 2, the assembly has the appearance shown in FIG- URE 2. At this instant, to terminate the assembly work, the part 1 should be rotated relatively to the part 2 through a quarter of a revolution so as to bring the markings 11 11 and 11 opposite one another; the markings 11 and 11 of the part 6 are arranged one on either side of the marking 11 of the part 7, as FIG- URE 3 shows. Then connecting bolts 12 are fixed in the holes 13 and 14 provided for this purpose in the plate 6 and the plate 3 respectively.

Dismounting is effected by carrying out the operations described hereinbefore in the reverse sense.

'FIG. 4 shows a portion of an internal combustion engine 15 having an overhead camshaft incorporating the invention. The end of shaft 5 is hollow and is mounted, with appreciable clearance, on a stud 16 fastened to a portion of the engine. Thus it is clear that when the part 1 bearing the cams is removed, the part 2 remains in the same timed relationship with the timing gear 17 via the chain 4.

In this way the result aimed at is effectively achieved, which is to permit the valve clearance to be regulated without having to alter the device driving the camshaft and consequently without altering the setting of the timing-gear.

I claim:

'1. In an internal combustion engine having an overhead mounted camshaft, a two-part camshaft comprising a driving part and a cam bearing part, said driving part being rotatably and substantially axially fixedly mounted in said engine and operatively connected to a timing gear thereof, said c-am bearing part being detachably mounted on said driving part through only movement normal to the axis of rotation of said driving part and substantially Without relative axial movement, and means for securing said parts together in axial alignment whereby engine valve clearance may be regulated without disturbing the camshaft drive and timing gear setting.

'2. A camshaft according to claim 1 in which said means for securing said parts together comprises a first flange fixedly mounted on said cam bearing part, said first flange being a substantially cylindrical plate with two spaced, parallel edges extending parallel to the longitudinal axis of said cam bearing part, a second flange fixedly mounted on said driving part, said second flange being a cylindrical plate with two spaced, upstanding 5 arcuate portions defining a channel therebetween, said channel being substantially equal in Width to the distance between said side edges of said first flange, said first flange being inserted into said second flange and rotated 90 to both position and secure said parts together.

3. A camshaft according to claim 1 further comprising means passing through both said flanges to thereby fixedly attach said parts together.

References Cited UNITED STATES PATENTS 218,723 8/1879 Faust 287-129 299,883 6/1884 Wallace 287-129 X 526,750 10/1894 Schnurr 287-129 X 1,229,893 6/1917 Crowell 123-90 FRED c. MATTERN, 111., Primary Examiner.

1O MILTON KAUFMAN, Examiner.

W. S. RATLIFF, Assistant Examiner. 

